The present invention relates to a safety device for an initiating device for a projectile, rocket or the like. The initiating device is located close to the charge in the projectile, and is intended to achieve positive initiation of this charge. It is moreover a requirement that the initiating device must be safe against accidental ignition during the transport and storage of the projectile.
In the prior art, an initiating device contains an initiating unit, particularly in the form of a striker pin, which ignites a priming charge or cap which thereafter ignites the charge in the projectile.
The priming charge typically comprises a detonator which, for safety reasons, can be applied in a movable member which can assume two positions, a first, safety position in which initiation of the charge in the projectile is prevented since the priming charge and the main charge are separated by a barrier, as well as a second, armed position, in which the priming charge can initiate the main charge.
It is previously known to arrange a movable member in the form of a safety rotor which is rotatable around an axis which is parallel to the direction of movement of the projectile. The rotor then assumes a certain angular position in the safe condition and can be turned to another angular position in the armed condition. The detonator is placed in an axial cavity in the rotor, and this cavity, in the armed condition, is aligned with an opening in the barrier so that the hot flame gases formed at the ignition of the detonator can pass through the opening and ignite the charge in the projectile by piercing the safety plate which protects the main charge.
In order to prevent the explosive charge from being set off unintentionally when the initiating device is in the safe condition, e.g. when the projectile is in storage or is being transported, it is desirable to have the barrier between the charged as thick as possible, so that the hot flame gases will not be capable of penetrating it if the detonator, for any reason, should be set off. On the other hand, it is a disadvantage if the charges are placed altogether too far from each other in the armed condition, as it may then happen that the hot flame gases from the detonator will not have sufficient force to penetrate the safety plate which, in itself, is thin. This contradictory condition has had the result that, for safety reasons, it has been necessary to resort to more or less sophisticated safety devices which for instance, utilize the rotation or acceleration of the projectile. A common feature of these devices is, however, that there is a great number of movable parts, which makes the manufacture complicated and makes the device susceptible to damage, and expensive.